In a remarkable discovery, astronomers have identified an Earth-like exoplanet orbiting a white dwarf star, potentially providing insight into the distant future of our own solar system. The exoplanet, with a mass approximately 1.9 times that of Earth, survived the violent phase when its host star expanded into a red giant before shrinking into a white dwarf. The finding offers new understanding of how planets might endure the tumultuous stages of stellar evolution.
Led by Keming Zhang from the University of California, the study utilized microlensing, a technique that magnifies distant celestial objects when the gravity of a foreground star bends the light from a background star. The white dwarf was nearly perfectly aligned with the background star, amplifying the event more than 1,000 times. This rare occurrence allowed researchers to detect even a small planet like this one and determine its mass and distance from the white dwarf.
Insights into Planetary Survival
The discovery reveals that this exoplanet managed to survive the destructive red giant phase, a period where a star swells and potentially engulfs nearby planets. This offers important clues about the fate of planets in solar systems, including our own, when their stars evolve into white dwarfs.
In addition to the exoplanet, the study also identified a brown dwarf orbiting the white dwarf an object approximately 30 times the mass of Jupiter.
As our Sun is predicted to go through a similar process, this finding provides a tantalizing preview of what may happen to Earth in billions of years, offering a broader perspective on planetary evolution and survival in extreme conditions.